1. Field of the Invention
The invention relates to an apparatus with a supporting frame, operative means supported by the frame and coupling means for securing the operative means to the frame, the frame including two first, parallel metal beams arranged side by side and coupled to two second metal beams arranged transversely to the first metal beams.
The invention also relates to an apparatus with a base, a supporting frame fixed to the base and defining two longitudinal, parallel guides, operative means supported by the frame, and coupling means for securing the operative means to the frame, at desired positions with respect to the guides.
Further, the invention relates to a gauge for checking features of pieces with rotational symmetry comprising means for positioning the piece to be checked; checking means; support means for carrying the positioning means and the checking means, the support means comprising a support base that defines two longitudinal parallel guides and intermediate support means with at least two transversal members longitudinally adjustable with respect to the support base; and fastening means with at least two pairs of rapid fastening devices, for clamping the transversal members to the support base.
Moreover, the invention relates to a process for manufacturing a supporting frame or sub-frame for an apparatus including operative means and coupling means for coupling the operative means to the supporting frame, the process including the step of assembling two longitudinal and &two transversal rigid profiled beams.
2. Description of the Prior Art
Mechanical apparatuses, such as machine tools and measuring machines or benches for measuring features --like linear dimensions --of workpieces, generally comprise support structures and operative means or devices carried by the support structures. Of course, the support structures may also have workholding functions. The support structures may be more or less stiff, flexible (as to manufacturing and/or use); and expensive, depending on the type of apparatus. Thus, they may range, for example, from modular flexible fixtures, welded tubular structures, integral baseplates --of hardened steel or cast iron --with tee--slots, cast iron beds, concrete or granite beds.
In particular, U.S. Pat. No. US-A-4,233,744 discloses a bench gauge including an integral plate defining three parallel guide slots for positioning gauging heads. The gauging heads can be clamped to the plate by means of connection screws passing through the slots and having screw heads accessible from the space under the plate. Of course, for precision machine tools, the stiffness of the support structures is a basic requisite and for this reason the relevant main support structures may be made of integral and massive bases and/or beds, while the secondary support structures may comprise welded tubular structures, baseplates with tee-slots, etc. GB-A-2177032 relates to a grinding machine comprising a massive understructure or base and a rigid superstructure or bed. The bed comprises a rigid frame which is assembled of several profiled beams including one or more hollow beams. Massive dedicated support structures, like cast iron beds or bases, especially designed for a specific apparatus or machine, are generally costly as far as materials and manufacturing are concerned. Moreover, their lead time, i.e. the time from order to delivery, is rather high. Flexible modular support structures may allow reduction of costs, but their stiffness may be poor, particularly when these structures are obtained by coupling most of or all the components by fasteners permitting disassembly. Thus, very high modularity and flexibility, both in the manufacturing and in the use, may be unsuitable for precision machine tools, measuring machines, and the like.
Another type of apparatus belonging to the field of the invention is already marketed by the assignee of the present invention and is described in the brochure "M53 BENCH GAUGE SYSTEM FOR SHAFTS" distributed as from November 1986 and consists in a bench gauge for checking diameters and longitudinal dimensions of shafts. It has a modular structure and is easily retoolable, to the purpose of checking, by utilizing the necessary components or modules and by adjusting their position, pieces of different shapes and/or dimensions. It comprises a longitudinal base consisting of a horizontal plate, with three feet and two vertical side plates screwed to the horizontal plate. Arranged at the top of the vertical plates are transversal support members that also have limit stop surfaces for cooperating with the vertical plates for keeping the members in a direction that is perpendicular to the longitudinal development direction of the plates. The transversal members carry comparative measuring cells, guiding and axial reference elements for facilitating the loading of the piece to be checked and determining its position along the longitudinal direction, and VEE-reference blocks for determining the position of the piece axis. These components are, at least partially, housed between the vertical plates. The measuring cells can be of the "snap" type for checking diameters, or of another type, in particular for checking longitudinal dimensions.
For clamping the transversal members to the vertical plates there are foreseen rapid fastening devices consisting of blocks clamped against a side of internal longitudinal grooves of the vertical plates, by means of bolts. The clamping is made from above the base formed by the horizontal and vertical plates. This known gauge has a massive structure that while on the one hand contributes to guarantee excellent measurement accuracy and repeatability, on the other hand gives rise to some inconveniences, in particular as far as the costs of the materials, the associated machining operations and the considerable overall dimensions are concerned.